3
Functions, Iterators, and Generators
The core of functional programming is the use of pure functions to map values from the input domain to the output range. Avoiding side effects reduces any dependence on variable assignment to maintain the state of a computation. We can’t purge the assignment statement from the Python language, but we can reduce our dependence on stateful objects. This means choosing among the available Python built-in functions and data structures to select those that don’t require stateful operations.
This chapter will present several Python features from a functional viewpoint, as follows:
Pure functions, free of side effects
Functions as objects that can be passed as arguments or returned as results
The use of Python’s object-oriented suffix notation and prefix notation
Using tuples as a way to create immutable objects, which avoid the confusion of state changes
Using iterable collections as our primary design tool for functional programming...
